A deck or porch can extend the livable area of a home considerably. Because decking and porches are oftentimes elevated with respect to the surrounding ground, the risk of falling off the deck or porch must be considered. Commonly, a guard rail is constructed at about waist height to prevent falling. However, a child or a seated adult could still fall from the deck despite the guard rail. To prevent this type of injury, pickets, narrow spaced-apart pieces of lumber, are fastened perpendicularly to the guardrail. Even in porches where typical mesh screening is attached below the guard rail, pickets are nonetheless necessary for safety because mesh screening cannot be counted on to prevent someone from falling off the porch or deck. Mesh screening may tear or come loose when subjected to lateral impact.
The area below the guard rail in a porch is referred to as infill. Two typical building code requirements apply to the infill. First, the infill section must be able to prevent a sphere of 10 cm (4 inches) from passing through any part of the infill. Second, when a 125-pound load is applied to a one-square-foot area, from either direction, the infill must not disengage from its framework. Pickets will meet that requirement when placed not more than 4 inches (10 cm) apart. Unfortunately, pickets partially obstruct the view from the deck and are an inconvenience to maintain. They also foreclose any alternate, aesthetic appearance for a deck or porch.
An infill that is safe but avoids the use of pickets would have several useful advantages.